U.S. patent number 9,277,607 [Application Number 14/618,668] was granted by the patent office on 2016-03-01 for lamp using solid state source.
This patent grant is currently assigned to ABL IP HOLDING LLC. The grantee listed for this patent is ABL IP HOLDING LLC. Invention is credited to Jack C. Rains, Jr., David P. Ramer.
United States Patent |
9,277,607 |
Ramer , et al. |
March 1, 2016 |
Lamp using solid state source
Abstract
A lamp includes a single string of light emitting diodes (LEDs),
driven in common, configured to cause the lamp to emit a visible
light output via a bulb. The lamp also includes a lighting industry
standard lamp base, which has connectors arranged in a standard
three-way lamp configuration, for providing electricity from a
three-way lamp socket. Circuitry connected to receive electricity
from the connectors of the lamp base as standard three-way control
setting inputs drives the string of LEDs. The circuitry is
configured to detect the standard three-way control setting inputs
and to adjust the common drive to the string of LEDs to selectively
produce a different visible light outputs of the lamp via the bulb
responsive to the three-way control setting inputs. The lamp may
also include nanophosphors pumped by emissions of the LEDs, so that
the lamp produces a white light output of particularly desirable
characteristics.
Inventors: |
Ramer; David P. (Reston,
VA), Rains, Jr.; Jack C. (Herndon, VA) |
Applicant: |
Name |
City |
State |
Country |
Type |
ABL IP HOLDING LLC |
Conyers |
GA |
US |
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Assignee: |
ABL IP HOLDING LLC (Conyers,
GA)
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Family
ID: |
44277125 |
Appl.
No.: |
14/618,668 |
Filed: |
February 10, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20150156833 A1 |
Jun 4, 2015 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14310518 |
Jun 20, 2014 |
8994269 |
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13915909 |
Jun 24, 2014 |
8760051 |
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13040395 |
Jun 19, 2014 |
8749131 |
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12697596 |
Jul 3, 2012 |
8212469 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21K
9/64 (20160801); H05B 45/37 (20200101); H05B
45/40 (20200101); F21V 23/009 (20130101); F21V
29/70 (20150115); H05B 45/20 (20200101); F21K
9/232 (20160801); F21V 29/40 (20130101); F21V
3/00 (20130101); F21V 29/63 (20150115); F21K
9/233 (20160801); H01J 61/44 (20130101); F21V
29/503 (20150115); H05B 45/10 (20200101); Y02B
20/00 (20130101); Y10S 977/95 (20130101); F21Y
2115/10 (20160801); Y10S 977/775 (20130101); Y10S
977/774 (20130101); H05B 45/12 (20200101) |
Current International
Class: |
H01J
7/44 (20060101); F21V 23/00 (20150101); H05B
33/08 (20060101); F21V 29/503 (20150101); F21V
29/70 (20150101); F21K 99/00 (20100101); H01J
61/44 (20060101); F21V 3/00 (20150101); F21V
29/00 (20150101) |
Field of
Search: |
;315/51,291,308
;313/110,317,498,503,512,563,567,637
;362/2,85,95,101,154,263-265,311.02,351,353,368,373,378
;977/773,774,775,950 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2144275 |
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Jan 2010 |
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EP |
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2008134056 |
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Nov 2008 |
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WO |
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2008155295 |
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Dec 2008 |
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WO |
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2009137053 |
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Nov 2009 |
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WO |
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Other References
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4, 2011, entitled "Lamp Using Solid State Source and Doped
Semiconductor Nanophosphor." cited by applicant .
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23, 2010, entitled "Tubular Lighting Products Using Solid State
Source and Semiconductor Nanophosphor, e.g. for Florescent Tube
Replacement." cited by applicant .
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filed, Jun. 12, 2013, entitled, "Lamp Using Solid State Source."
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Receipt and New Utility Transmittal. cited by applicant .
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applicant .
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International Searching Authority issued in International Patent
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1, 2010 entitled Lamp Using Solid State Source and Doped
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Emitters: Pure and Tunable Impurity Emissions in ZnSe
Nonocrystals", Nov. 24, 2005, 127, pp. 17586-17587, J.A, Chem, Soc.
Communications, web publication. cited by applicant .
"Energy Star Program Requirements for solid state Lighting
Luminaires Eligibility Criteria-Version 1.0", Manual, Sep. 12,
2007. cited by applicant .
Yin, Yadong and A. Paul Alivasatos, "Colloidal nanocrystal
synthesis and the organic-inorganic interface", Insight Review,
Sep. 25, 2005, pp. 664-670, Nature vol. 437. cited by applicant
.
"Final Report: Highly Bright, Heavy Metal-Free, and stable Doped
Semiconductor Nanophosphors for Economical Solid State Lighting
Alternatives", Report, Nov. 12, 2009, pp. 1-3, National Center for
Environmental Research, we publication. cited by applicant .
"Solid-State Lighting: Development of White LEDs Using
Nanophosphor-InP Blends", Report, Oct. 26, 2009, p. 1, U.S
Department of Energy--Energy Efficiency and Renewable Energy, web
publication. cited by applicant .
"Solid-State Lighting: Improved Light Extraction Efficiencies of
White pc-LEDs for SSL by Using Non-Toxic, Non-Scattering, Bright,
and stable Doped ZnSe Quantum Dot Nanophosphors (Phase I)", Report,
Oct. 26, 2009, pp. 1-2, U.S. Department of Energy--Energy
Efficiency and Renewable Energy, web publication. cited by
applicant .
"Chemistry--All in the Dope," Editor's Choice, Dec. 9, 2005,
Science, vol. 310, p. 1, AAAS, web publication. cited by applicant
.
"D-dots: Heavy Metal Free Doped Semiconductor Nanocrystals",
Technical Specifications, etc. Dec. 1, 2009, pp. 1-2, NN-Labs, LLC
(Nanomaterials & Nanofabrication Laboratories), CdSe/ZnS
Semiconductor Nanocrystals, web publication. cited by applicant
.
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20, 2014, entitled Lamp Using Solid State Source. cited by
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14/310,518, filed Jun. 20, 2014. cited by applicant.
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Primary Examiner: Tran; Thuy Vinh
Attorney, Agent or Firm: RatnerPrestia
Parent Case Text
RELATED APPLICATIONS
This application is a Continuation of U.S. patent application Ser.
No. 14/310,518, filed on Jun. 20, 2014 (U.S. Pat. No. 8,994,269),
which is a Continuation of U.S. patent application Ser. No.
13/915,909, filed on Jun. 12, 2013 (U.S. Pat. No. 8,760,051), which
is a Continuation of U.S. patent application Ser. No. 13/040,395,
filed on Mar. 4, 2011 (U.S. Pat. No. 8,749,131), which is a
Continuation of U.S. patent application Ser. No. 12/697,596, filed
on Feb. 1, 2010 (U.S. Pat. No. 8,212,469), the contents of the
entire disclosures of all of those applications being incorporated
herein entirely by reference.
Claims
What is claimed is:
1. A light engine, comprising: a solid state source comprising a
plurality of light emitting diodes (LEDs); a lighting industry
standard lamp base, including connectors arranged in a standard
three-way lamp configuration, for providing electricity from a
three-way lamp socket; a housing mechanically connected to the lamp
base; and circuitry in the housing connected to receive electricity
from the connectors of the lamp base as standard three-way control
setting inputs and to drive the LEDs, wherein the circuitry is
configured to detect the standard three-way control setting inputs
and to adjust the drive to the LEDs to selectively produce a
plurality of different outputs responsive to the three-way control
setting inputs.
2. The light engine of claim 1, wherein the circuitry is configured
to convert alternating current electricity provided through the
lamp base to direct current electricity and is connected to the
LEDs to drive the LEDs with the direct current electricity.
3. The light engine of claim 1, further comprising: a heat sink;
and a thermal interface for transfer of heat from the LEDs to the
heat sink.
4. The light engine of claim 3, wherein at least the thermal
interface is within the housing.
5. The light engine of claim 1, wherein the circuitry comprises:
logic to recognize the switch states of the three-way control
setting inputs; and a driver responsive to recognition of switch
state of the three-way control setting inputs by the logic to
control the current applied to drive the LEDs to adjust output of
the LEDs depending on the recognized switch state.
6. The light engine of claim 5, wherein the logic and/or the driver
are configured to adjust the drive to the LEDs to selectively
produce different output levels corresponding to the three-way
control setting inputs.
7. The light engine of claim 5, wherein the LEDs are configured to
form: a first string comprising a first number of one or more LEDs
driven in common by the circuitry; and a second string comprising a
second number of LEDs larger than the first number driven in common
by the circuitry.
8. The light engine of claim 7, wherein the logic and/or driver are
configured to adjust the drive to the first and second strings of
LEDs to selectively produce different output levels corresponding
to the three-way control setting inputs.
9. The light engine of claim 1, wherein: the LEDs are configured to
form: a first string comprising a first number of one or more LEDs
driven in common by the circuitry; and a second string comprising a
second number of LEDs larger than the first number driven in common
by the circuitry; the circuitry comprises: logic to recognize the
switch states of the three-way control setting inputs; and a first
driver and a second driver responsive to recognition of switch
state of the three-way control setting inputs by the logic to
control the current applied to drive the first and second strings
of LEDs to adjust output of the first and second strings of LEDs
depending on the recognized switch state; and the logic and/or
drivers are configured to adjust the drive to the first and second
strings of LEDs to selectively produce different output levels
corresponding to the three-way control setting inputs.
10. The light engine of claim 1, wherein: the LEDs are connected
together with each other to form a single commonly driven solid
state light source; the circuitry comprises: logic to recognize the
switch states of the three-way control setting inputs; and a driver
responsive to recognition of switch state of the three-way control
setting inputs by the logic to control the current applied to drive
the LEDs to adjust output of the LEDs depending on the recognized
switch state; and the logic and/or drivers are configured to
commonly drive the LEDs of the solid state light source together as
a group to selectively produce different output levels
corresponding to the three-way control setting inputs.
11. The light engine of claim 1, wherein: the solid state source is
configured to cause a visible light output via a bulb; and the
housing is configured to support the bulb in a position to receive
electromagnetic energy from the solid state source.
12. A light engine, comprising: light emitting diodes (LEDs)
configured to form a solid state light source; a heat sink; a
thermal interface for transfer of heat from the LEDs to the heat
sink; a lighting industry standard lamp base for providing
electricity from a lamp socket, the lamp base including connectors
arranged in a standard three-way lamp configuration, for providing
electricity from a three-way lamp socket; and circuitry, housed as
part of the light engine and connected to receive electricity from
the lamp base, configured to detect the standard three-way control
setting inputs and to adjust the drive to the LEDs to selectively
produce a plurality of different output levels responsive to the
three-way control setting inputs.
13. The light engine of claim 12, wherein the circuitry is
configured to convert alternating current electricity provided
through the lamp base to direct current electricity and is
connected to drive the LEDs with the direct current
electricity.
14. The light engine of claim 12, wherein the circuitry comprises:
logic to recognize the switch states of the three-way control
setting inputs; and a driver responsive to recognition of switch
state of the three-way control setting inputs by the logic to
control current applied to drive the LEDs to adjust output level of
the LEDs depending on the recognized switch state.
15. The light engine of claim 14, wherein the logic and/or the
driver are configured to adjust the drive to the LEDs to
selectively produce three different output levels corresponding to
the three-way control setting inputs.
16. The light engine of claim 14, wherein the LEDs are configured
to form: a first string comprising a first number of one or more
LEDs driven in common by the circuitry; and a second string
comprising a second number of LEDs larger than the first number
driven in common by the circuitry.
17. The light engine of claim 16, wherein the logic and/or driver
are configured to adjust the drive to the first and second strings
of LEDs to selectively produce different output levels
corresponding to the three-way control setting inputs.
18. The light engine of claim 12, wherein: the LEDs are configured
to form: a first string comprising a first number of one or more
LEDs driven in common by the circuitry; and a second string
comprising a second number of LEDs larger than the first number
driven in common by the circuitry; the circuitry comprises: logic
to recognize the switch states of the three-way control setting
inputs; and a first driver and a second driver responsive to
recognition of switch state of the three-way control setting inputs
by the logic to control the current applied to drive the first and
second strings of LEDs to adjust output of the first and second
strings of LEDs depending on the recognized switch state; and the
logic and/or drivers are configured to adjust the drive to the
first and second strings of LEDs to selectively produce different
output levels corresponding to the three-way control setting
inputs.
19. The light engine of claim 12, wherein: the LEDs are connected
together with each other to form a single commonly driven solid
state light source; the circuitry comprises: logic to recognize the
switch states of the three-way control setting inputs; and a driver
responsive to recognition of switch state of the three-way control
setting inputs by the logic to control the current applied to drive
the LEDs to adjust output of the LEDs depending on the recognized
switch state; and the logic and/or drivers are configured to
commonly drive the LEDs of the solid state light source together as
a group to selectively produce different output levels
corresponding to the three-way control setting inputs.
20. A lamp for producing visible light, comprising: a bulb; and a
light engine comprising: a solid state source comprising a
plurality of light emitting diodes (LEDs), configured to cause the
lamp to emit a visible light output via the bulb; a lighting
industry standard lamp base, including connectors arranged in a
standard three-way lamp configuration, for providing electricity
from a three-way lamp socket; a housing supporting the bulb in a
position to receive electromagnetic energy from the solid state
source, the housing being mechanically connected to the lamp base;
and circuitry in the housing connected to receive electricity from
the connectors of the lamp base as standard three-way control
setting inputs and to drive the LEDs, wherein the circuitry is
configured to detect the standard three-way control setting inputs
and to adjust the drive to the LEDs to selectively produce a
plurality of different visible light outputs of the lamp via the
bulb responsive to the three-way control setting inputs.
21. The lamp of claim 20, wherein the light engine further
comprises: a heat sink; and a thermal interface for transfer of
heat from the LEDs to the heat sink.
22. The lamp of claim 21, wherein at least the thermal interface is
within the housing.
23. The lamp of claim 20, wherein: the circuitry comprises: logic
to recognize switch states of the three-way control setting inputs;
and a driver responsive to recognition of switch state of the
three-way control setting inputs by the logic to control current
applied to drive the LEDs to adjust output of the LEDs depending on
the recognized switch state; and the logic and/or the driver are
configured to adjust the drive to the LEDs to selectively produce
different light output levels for the visible light output of the
lamp via the bulb corresponding to the three-way control setting
inputs.
Description
BACKGROUND
Recent years have seen a rapid expansion in the performance of
solid state lighting devices such as light emitting devices (LEDs);
and with improved performance, there has been an attendant
expansion in the variety of applications for such devices. For
example, rapid improvements in semiconductors and related
manufacturing technologies are driving a trend in the lighting
industry toward the use of light emitting diodes (LEDs) or other
solid state light sources to produce light for general lighting
applications to meet the need for more efficient lighting
technologies and to address ever increasing costs of energy along
with concerns about global warming due to consumption of fossil
fuels to generate energy. LED solutions also are more
environmentally friendly than competing technologies, such as
compact fluorescent lamps, for replacements for traditional
incandescent lamps.
The actual solid state light sources, however, produce light of
specific limited spectral characteristics. To obtain white light of
a desired characteristic and/or other desirable light colors, one
approach uses sources that produce light of two or more different
colors or wavelengths and one or more optical processing elements
to combine or mix the light of the various wavelengths to produce
the desired characteristic in the output light. In recent years,
techniques have also been developed to shift or enhance the
characteristics of light generated by solid state sources using
phosphors, including for generating white light using LEDs.
Phosphor based techniques for generating white light from LEDs,
currently favored by LED manufacturers, include UV or Blue LED
pumped phosphors. In addition to traditional phosphors,
semiconductor nanophosphors have been used more recently. The
phosphor materials may be provided as part of the LED package (on
or in close proximity to the actual semiconductor chip), or the
phosphor materials may be provided remotely (e.g. on or in
association with a macro optical processing element such as a
diffuser or reflector outside the LED package). The remote phosphor
based solutions have advantages, for example, in that the color
characteristics of the fixture output are more repeatable, whereas
solutions using sets of different color LEDs and/or lighting
fixtures with the phosphors inside the LED packages tend to vary
somewhat in light output color from fixture to fixture, due to
differences in the light output properties of different sets of
LEDs (due to lax manufacturing tolerances of the LEDs).
Hence, solid state lighting technologies have advanced considerably
in recent years, and such advances have encompassed any number of
actual LED based lamp products as well as a variety of additional
proposals for LED based lamps. However, there is still room for
further improvement in the context of solid state lamp products
that are compatible with existing standardized light sockets and
therefore might be adopted as replacements for conventional
incandescent lamps, compact fluorescent lamps, or other similar
older technology lamps.
For example, there is always a need for techniques to still further
improve efficiency of solid state lamps, to reduce energy
consumption. Also, any new solution should provide a light output
distribution that generally conforms to that of the standard lamp
it may replace, so as to provide a light output of color, intensity
and distribution that meets or exceeds expectations arising from
the older replaced technologies. As another example of a desirable
characteristic for a solid state lamp, for general lighting
applications, it is desirable to consistently provide light outputs
of acceptable characteristics (e.g. white light of a desired color
rendering index and/or color temperature) in a consistent
repeatable manner from one instance of a lamp product to
another.
Of course, to be commercially competitive with alternative lamp
technologies requires an elegant overall solution. For example, the
product should be as simple as possible so as to allow relatively
low cost manufacturing. Relatively acceptable/pleasing form factors
similar to those of well accepted incandescent lamps may be
desirable. Solid state devices have advantages of relatively high
dependability and long life. However, within the desired lamp form
factor/configuration, there are a variety of technical issues
relating to use of solid state devices that still must be met, such
as efficient electrical drive of the solid state light emitters,
efficient processing of the light for the desired output and/or
adequate dissipation of the heat that the solid state devices
generate.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawing figures depict one or more implementations in accord
with the present teachings, by way of example only, not by way of
limitation. In the figures, like reference numerals refer to the
same or similar elements.
FIG. 1 a cross-sectional view of a first example of a solid state
lamp, for lighting applications, which uses a solid state source
and one or more doped nanophosphors pumped by energy from the
source to produce visible light.
FIG. 2 is a plan view of the LEDs and reflector of the lamp of FIG.
1.
FIGS. 3A to 3C are cross-sectional views of several alternate
examples of the glass bulb as may be used in place of the bulb in
the exemplary lamp of FIG. 1.
FIG. 4 is a color chart showing the black body curve and tolerance
quadrangles along that curve for chromaticities corresponding to
several desired color temperature ranges for lamps configured for
white light applications.
FIG. 5 is a graph of absorption and emission spectra of a number of
doped semiconductor nanophosphors.
FIG. 6A is a graph of emission spectra of three of the doped
semiconductor nanophosphors selected for use in an exemplary solid
state light emitting lamp as well as the spectrum of the white
light produced by combining the spectral emissions from those three
phosphors.
FIG. 6B is a graph of emission spectra of four doped semiconductor
nanophosphors, in this case, for red, green, blue and yellow
emissions, as well as the spectrum of the white light produced by
combining the spectral emissions from those four phosphors.
FIG. 7 is a cross-sectional view of another example of a solid
state lamp, in which the glass bulb forms a light transmissive
glass enclosure enclosing a separate internal container for the
material bearing the nanophosphors.
FIG. 8 is a cross-sectional view of an example of a solid state
lamp, similar to that of FIG. 7, but in which the glass bulb
enclosure provides a form factor and output distribution of a
R-lamp.
FIG. 9 is a cross-sectional view of an example of a solid state
lamp, similar to that of FIG. 7, but in which the glass bulb
enclosure provides a form factor and output distribution of a
Par-lamp.
FIG. 10 is a plan view of a screw type lamp base, such as an Edison
base or a candelabra base.
FIG. 11 is an example of the LED and drive circuitry, for driving a
string of LEDs from AC line current (rectified in this example, but
not converted to DC).
FIG. 12 is an example of the LED and drive circuitry, in which a
LED driver converts AC to DC to drive the LEDs.
FIG. 13 is a plan view of a three-way dimming screw type lamp base,
such as for a three-way mogul lamp base or a three-way medium lamp
base.
FIG. 14 shows the LED and circuit arrangement for a three-way
dimming lamp, using two different LED strings and associated drive
circuitry, for driving two strings of LEDs from AC line current
(rectified in this example, but not converted to DC).
FIG. 15 shows the LED and circuit arrangement for a three-way
dimming lamp, using two different LED strings and two associated
LED driver circuits for converting AC to DC to drive the respective
strings of LEDs.
FIG. 16 shows the LED and circuit arrangement for a three-way
dimming lamp, but using a single string of LEDs driven in common,
where the circuitry converts AC to DC but also is responsive to
conventional three-way input switch settings to set corresponding
drive levels for driving the LED string.
DETAILED DESCRIPTION
In the following detailed description, numerous specific details
are set forth by way of examples in order to provide a thorough
understanding of the relevant teachings. However, it should be
apparent to those skilled in the art that the present teachings may
be practiced without such details. In other instances, well known
methods, procedures, components, and/or circuitry have been
described at a relatively high-level, without detail, in order to
avoid unnecessarily obscuring aspects of the present teachings.
The various examples of solid state lamps disclosed herein may be
used in common lighting fixtures, floor lamps and table lamps, or
the like, e.g. as replacements for incandescent or compact
fluorescent lamps. Reference now is made in detail to the examples
illustrated in the accompanying drawings and discussed below.
FIG. 1 illustrates the first example of a solid state lamp 10, in
cross section. The exemplary lamp 10 may be utilized in a variety
of lighting applications. The lamp, for example includes a solid
state source for producing electromagnetic energy. The solid state
source is a semiconductor based structure for emitting
electromagnetic energy of one or more wavelengths within the range.
In the example, the source comprises one or more light emitting
diode (LED) devices, although other semiconductor devices might be
used. Hence, in the example of FIG. 1, the source takes the form of
a number of LEDs 11.
It is contemplated that the LEDs 11 could be of any type rated to
emit energy of wavelengths from the blue/green region around 460 nm
down into the UV range below 380 nm. As discussed below, the
exemplary nanophosphors have absorption spectra having upper limits
around 430 nm, although other doped semiconductor nanophosphors may
have somewhat higher limits on the wavelength absorption spectra
and therefore may be used with LEDs or other solid state devices
rated for emitting wavelengths as high as say 460 nm. In the
specific examples, particularly those for white light lamp
applications, the LEDs 11 are near UV LEDs rated for emission
somewhere in the 380-420 nm range, although UV LEDs could be used
alone or in combination with near UV LEDs even with the exemplary
nanophosphors. A specific example of a near UV LED, used in several
of the specific white lamp examples, is rated for 405 nm
emission.
The structure of a LED includes a semiconductor light emitting
diode chip, within a package or enclosure. A transparent portion
(typically formed of glass, plastic or the like), of the package
that encloses the chip, allows for emission of the electromagnetic
energy in the desired direction. Many such source packages include
internal reflectors to direct energy in the desired direction and
reduce internal losses. Each LED 11 is rated for emission somewhere
in the range at or below 460 nm. For a white light lamp
application, the LEDs would be rated to emit near UV
electromagnetic energy of a wavelength in the 380-420 nm range,
such as 405 nm. Semiconductor devices such as the LEDs 11 exhibit
emission spectra having a relatively narrow peak at a predominant
wavelength, although some such devices may have a number of peaks
in their emission spectra. Often, manufacturers rate such devices
with respect to the intended wavelength of the predominant peak,
although there is some variation or tolerance around the rated
value, from device to device. LED devices, such as devices 11, for
use in a lamp 10, will have a predominant wavelength in the range
at or below 460 nm. For example, each LED 11 in the example of FIG.
1 may rated for a 405 nm output, which means that it has a
predominant peak in its emission spectra at or about 405 nm (within
the manufacturer's tolerance range of that rated wavelength value).
The lamp 10, however, may use devices that have additional peaks in
their emission spectra. The structural configuration of the LEDs 11
of the solid state source is presented above by way of example
only.
One or more doped semiconductor nanophosphors are used in the lamp
10 to convert energy from the source into visible light of one or
more wavelengths to produce a desired characteristic of the visible
light output of the lamp. The doped semiconductor nanophosphors are
remotely deployed, in that they are outside of the individual
device packages or housings of the LEDs 11. For this purpose, the
exemplary lamp includes a container formed of optically
transmissive material coupled to receive near UV electromagnetic
energy from the LEDs 11 forming the solid state source. The
container contains a material, which at least substantially fills
the interior volume of the container. For example, if a liquid is
used, there may be some gas in the container as well, although the
gas should not include oxygen as oxygen tends to degrade the
nanophosphors. In this example, the lamp includes at least one
doped semiconductor nanophosphor dispersed in the material in the
container.
The material may be a solid, although liquid or gaseous materials
may help to improve the florescent emissions by the nanophosphors
in the material. For example, alcohol, oils (synthetic, vegetable,
silicon or other oils) or other liquid media may be used. A
silicone material, however, may be cured to form a hardened
material, at least along the exterior (to possibly serve as an
integral container), or to form a solid throughout the intended
volume. If hardened silicon is used, however, a glass container
still may be used to provide an oxygen barrier to reduce
nanophosphor degradation due to exposure to oxygen.
If a gas is used, the gaseous material, for example, may be
hydrogen gas, any of the inert gases, and possibly some hydrocarbon
based gases. Combinations of one or more such types of gases might
be used.
Hence, although the material in the container may be a solid,
further discussion of the examples will assume use of a liquid or
gaseous material. The lamp 10 in the first example includes a glass
bulb 13. In some later examples, there is a separate container, and
the glass bulb encloses the container. In this first example,
however, the glass of the bulb 13 serves as the container. The
container wall(s) are transmissive with respect to at least a
substantial portion of the visible light spectrum. For example, the
glass of the bulb 13 will be thick enough (as represented by the
wider lines), to provide ample strength to contain a liquid or gas
material if used to bear the doped semiconductor nanophosphors in
suspension, as shown at 15. However, the material of the bulb will
allow transmissive entry of energy from the LEDs 11 to reach the
nanophosphors in the material 15 and will allow transmissive output
of visible light principally from the excited nanophosphors.
The glass bulb/container 13 receives energy from the LEDs 11
through a surface of the bulb, referred to here as an optical input
coupling surface 13c. The example shows the surface 13c as a flat
surface, although obviously outer contours may be used. Light
output from the lamp 10 emerges through one or more other surfaces
of the bulb 13, referred to here as output surface 13o. In the
example, the bulb 13 here is glass, although other appropriate
transmissive materials may be used. For a diffuse outward
appearance of the bulb, the output surface(s) 13o may be frosted
white or translucent, although the optical input coupling surface
13c might still be transparent to reduce reflection of energy from
the LEDs 11 back towards the LEDs. Alternatively, the output
surface 13o may be transparent.
For some lighting applications where a single color is desirable
rather than white, the lamp might use a single type of nanophosphor
in the material. For a yellow `bug lamp` type application, for
example, the one nanophosphor would be of a type that produces
yellow emission in response to pumping energy from the LEDs. For a
red lamp type application, as another example, the one nanophosphor
would be of a type that produces predominantly red light emission
in response to pumping energy from the LEDs. The upper limits of
the absorption spectra of the exemplary nanophosphors are all at or
around 430 nm, therefore, the LEDs used in such a monochromatic
lamp would emit energy in a wavelength range of 430 nm and below.
In many examples, the lamp produces white light of desirable
characteristics using a number of doped semiconductor
nanophosphors, and further discussion of the examples including
that of FIG. 1 will concentrate on such white light
implementations.
Hence for further discussion, we will assume that the container
formed by the glass bulb 13 is at least substantially filled with a
liquid or gaseous material 15 bearing a number of different doped
semiconductor nanophosphors dispersed in the liquid or gaseous
material 15. Also, for further discussion, we will assume that the
LEDs 11 are near UV emitting LEDs, such as 405 nm LEDs or other
types of LEDs rated to emit somewhere in the wavelength range of
380-420 nm. Each of the doped semiconductor nanophosphors is of a
type excited in response to near UV electromagnetic energy from the
LEDs 11 of the solid state source. When so excited, each doped
semiconductor nanophosphor re-emits visible light of a different
spectrum. However, each such emission spectrum has substantially no
overlap with absorption spectra of the doped semiconductor
nanophosphors. When excited by the electromagnetic energy received
from the LEDs 11, the doped semiconductor nanophosphors together
produce visible light output for the lamp 10 through the exterior
surface(s) of the glass bulb 13.
The liquid or gaseous material 15 with the doped semiconductor
nanophosphors dispersed therein appears at least substantially
clear when the lamp 10 is off. For example, alcohol, oils
(synthetic, vegetable or other oils) or other clear liquid media
may be used, or the liquid material may be a relatively clear
hydrocarbon based compound or the like. Exemplary gases include
hydrogen gas, clear inert gases and clear hydrocarbon based gases.
The doped semiconductor nanophosphors in the specific examples
described below absorb energy in the near UV and UV ranges. The
upper limits of the absorption spectra of the exemplary
nanophosphors are all at or around 430 nm, however, the exemplary
nanophosphors are relatively insensitive to other ranges of visible
light often found in natural or other ambient white visible light.
Hence, when the lamp 10 is off, the doped semiconductor
nanophosphors exhibit little or no light emissions that might
otherwise be perceived as color by a human observer. Even though
not emitting, the particles of the doped semiconductor
nanophosphors may have some color, but due to their small size and
dispersion in the material, the overall effect is that the material
15 appears at least substantially clear to the human observer, that
is to say it has little or no perceptible tint.
The LEDs 11 are mounted on a circuit board 17. The exemplary lamp
10 also includes circuitry 19. Although drive from DC sources is
contemplated for use in existing DC lighting systems, the examples
discussed in detail utilize circuitry configured for driving the
LEDs 11 in response to alternating current electricity, such as
from the typical AC main lines. The circuitry may be on the same
board 17 as the LEDs or disposed separately within the lamp 10 and
electrically connected to the LEDs 11. Electrical connections of
the circuitry 19 to the LEDs and the lamp base are omitted here for
simplicity. Several examples of the drive circuitry 19 are
discussed later with regard to FIGS. 11, 12 and 14-16.
A housing 21 at least encloses the circuitry 19. In the example,
the housing 21 together with a lamp base 23 and a face of the glass
bulb 13 also enclose the LEDs 11. The lamp 10 has a lighting
industry standard lamp base 23 mechanically connected to the
housing and electrically connected to provide alternating current
electricity to the circuitry 19 for driving the LEDs 11.
The lamp base 23 may be any common standard type of lamp base, to
permit use of the lamp 10 in a particular type of lamp socket.
Common examples include an Edison base, a mogul base, a candelabra
base and a bi-pin base. The lamp base may have electrical
connections for a single intensity setting or additional contacts
in support of three-way intensity setting/dimming.
The exemplary lamp 10 of FIG. 1 may include one or more features
intended to prompt optical efficiency. Hence, as illustrated, the
lamp 10 includes a diffuse reflector 25. The circuit board 17 has a
surface on which the LEDs 11 are mounted, so as to face toward the
light receiving surface of the glass bulb 13 containing the
nanophosphor bearing material 15. The reflector 25 covers parts of
that surface of the circuit board 17 in one or more regions between
the LEDs 11. FIG. 2 is a view of the LEDs 11 and the reflector 25.
When excited, the nanophosphors in the material 15 emit light in
many different directions, and at least some of that light would be
directed back toward the LEDs 11 and the circuit board 17. The
diffuse reflector 25 helps to redirect much of that light back
through the glass bulb 13 for inclusion in the output light
distribution.
The lamp 10 may use one or any number of LEDs 11 sufficient to
provide a desired output intensity. The example of FIG. 2 shows
seven LEDs 11, although the lamp 10 may have more or less LEDs than
in that example.
There may be some air gap between the emitter outputs of the LEDs
11 and the facing optical coupling surface 13c of the glass bulb
container 13 (FIG. 1). However, to improve out-coupling of the
energy from the LEDs 11 into the light transmissive glass of the
bulb 13, it may be helpful to provide an optical grease, glue or
gel 27 between the surface 13c of the glass bulb 13 and the optical
outputs of the LEDs 11. This index matching material 27 eliminates
any air gap and provides refractive index matching relative to the
material of the glass bulb container 13.
The examples also encompass technologies to provide good heat
conductivity so as to facilitate dissipation of heat generated
during operation of the LEDs 11. Hence, the exemplary lamp 10
includes one or more elements forming a heat dissipater within the
housing for receiving and dissipating heat produced by the LEDs 11.
Active dissipation, passive dissipation or a combination thereof
may be used. The lamp 10 of FIG. 1, for example, includes a thermal
interface layer 31 abutting a surface of the circuit board 17,
which conducts heat from the LEDs and the board to a heat sink
arrangement 33 shown by way of example as a number of fins within
the housing 21. The housing 21 also has one or more openings or air
vents 35, for allowing passage of air through the housing 21, to
dissipate heat from the fins of the heat sink 33.
The thermal interface layer 31, the heat sink 33 and the vents 35
are passive elements in that they do not consume additional power
as part of their respective heat dissipation functions. However,
the lamp 10 may include an active heat dissipation element that
draws power to cool or otherwise dissipate heat generated by
operations of the LEDs 11. Examples of active cooling elements
include fans, Peltier devices or the like. The lamp 10 of FIG. 1
utilizes one or more membronic cooling elements. A membronic
cooling element comprises a membrane that vibrates in response to
electrical power to produce an airflow. An example of a membronic
cooling element is a SynJet.RTM. sold by Nuventix. In the example
of FIG. 1, the membronic cooling element 37 operates like a fan or
air jet for circulating air across the heat sink 33 and through the
air vents 35.
In the orientation illustrated in FIG. 1, white light from the
semiconductor nanophosphor excitation is dispersed upwards and
laterally, for example, for omni-directional lighting of a room
from a table or floor lamp. The orientation shown, however, is
purely illustrative. The lamp 10 may be oriented in any other
direction appropriate for the desired lighting application,
including downward, any sideways direction, various intermediate
angles, etc.
In the example of FIG. 1, the glass bulb 13, containing the
material 15 with the doped semiconductor nanophosphors produces a
wide dispersion of output light, which is relatively
omni-directional (except directly downward in the illustrated
orientation). Such a light output intensity distribution
corresponds to that currently offered by A-lamps. Other
bulb/container structures, however, may be used; and a few examples
are presented in FIGS. 3A to 3C. FIG. 3A shows a globe-and-stem
arrangement for A-Lamp type omni-directional lighting. FIGS. 3B and
3C show R-lamp and Par-lamp style bulbs for different directed
lighting applications. As represented by the double lines, some
internal surfaces of the directional bulbs may be reflective, to
promote the desired output distributions.
The lamp 10 of FIG. 1 has one of several industry standard lamp
bases 23, shown in the illustration as a type of screw-in base. The
glass bulb 13 exhibits a form factor within standard size, and the
output distribution of light emitted via the bulb 13 conforms to
industry accepted specifications, for a particular type of lamp
product. Those skilled in the art will appreciate that these
aspects of the lamp 10 facilitate use of the lamp as a replacement
for existing lamps, such as incandescent lamps and compact
fluorescent lamps.
The housing 21, the base 23 and components contained in the housing
21 can be combined with a bulb/container in one of a variety of
different shapes. As such, these elements together may be described
as a `light engine` portion of the lamp for generating the near UV
energy. Theoretically, the engine and bulb could be modular in
design to allow a user to interchange glass bulbs, but in practice
the lamp is an integral product. The light engine may be
standardized across several different lamp product lines. In the
examples of FIGS. 1 and 3, housing 21, the base 23 and components
contained in the housing 21 could be the same for A-lamps (bulb of
FIG. 1 or bulb of FIG. 3A), R-lamps (bulb of FIG. 3B), Par-lamps
(bulb of FIG. 3C) or other styles of lamps. A different base can be
substituted for the screw base 23 shown in FIG. 1, to produce a
lamp product configured for a different socket design.
As outlined above, the lamp 10 will include or have associated
therewith remote semiconductor nanophosphors in a container that is
external to the LEDs 11 of the solid state source. As such, the
phosphors are located apart from the semiconductor chip of the LEDs
11 used in the particular lamp 10, that is to say remotely
deployed.
The semiconductor nanophosphors are dispersed, e.g. in suspension,
in a liquid or gaseous material 15, within a container (bulb 13 in
the lamp 10 of FIG. 1). The liquid or gaseous medium preferably
exhibits high transmissivity and/or low absorption to light of the
relevant wavelengths, although it may be transparent or somewhat
translucent. Although alcohol, oils (synthetic, vegetable, silicon
or other oils) or other media may be used, in the example of FIG.
1, the medium may be a hydrocarbon material, in either a liquid or
gaseous state.
In an example of a white light type lamp, the doped semiconductor
nanophosphors in the material shown at 15 are of types or
configurations (e.g. selected types of doped semiconductor
nanophosphors) excitable by the near UV energy from LEDs 11 forming
the solid state source. Together, the excited nanophosphors produce
output light that is at least substantially white and has a color
rendering index (CRI) of 75 or higher. The lamp output light
produced by this near UV excitation of the semiconductor
nanophosphors exhibits color temperature in one of several desired
ranges along the black body curve. Different light lamps 10
designed for different color temperatures of white output light
would use different formulations of mixtures of doped semiconductor
nanophosphors. The white output light of the lamp 10 exhibits color
temperature in one of four specific ranges along the black body
curve listed in Table 1 below.
TABLE-US-00001 TABLE 1 Nominal Color Temperatures and Corresponding
Color Temperature Ranges Nominal Color Color Temp. Temp. (.degree.
Kelvin) Range (.degree. Kelvin) 2700 2725 .+-. 145 3000 3045 .+-.
175 3500 3465 .+-. 245 4000 3985 .+-. 275
In Table 1, each nominal color temperature value represents the
rated or advertised temperature as would apply to particular lamp
products having an output color temperature within the
corresponding range. The color temperature ranges fall along the
black body curve. FIG. 4 shows the outline of the CIE 1931 color
chart, and the curve across a portion of the chart represents a
section of the black body curve that includes the desired CIE color
temperature (CCT) ranges. The light may also vary somewhat in terms
of chromaticity from the coordinates on the black body curve. The
quadrangles shown in the drawing represent the respective ranges of
chromaticity for the nominal CCT values. Each quadrangle is defined
by the range of CCT and the distance from the black body curve.
Table 2 below provides chromaticity specifications for the four
color temperature ranges. The x, y coordinates define the center
points on the black body curve and the vertices of the tolerance
quadrangles diagrammatically illustrated in the color chart of FIG.
4.
TABLE-US-00002 TABLE 2 Chromaticity Specification for the Four
Nominal Values/CCT Ranges CCT Range 2725 .+-. 145 3045 .+-. 175
3465 .+-. 245 3985 .+-. 275 Nominal CCT 2700.degree. K 3000.degree.
K 3500.degree. K 4000.degree. K x y x y x y x y Center point 0.4578
0.4101 0.4338 0.4030 0.4073 0.3917 0.3818 0.3797 0.4813 0.4319
0.4562 0.4260 0.4299 0.4165 0.4006 0.4044 Tolerance 0.4562 0.426
0.4299 0.4165 0.3996 0.4015 0.3736 0.3874 Quadrangle 0.4373 0.3893
0.4147 0.3814 0.3889 0.369 0.367 0.3578 0.4593 0.3944 0.4373 0.3893
0.4147 0.3814 0.3898 0.3716
The solid state lamp 10 could use a variety of different
combinations of semiconductor nanophosphors to produce such an
output. Examples of suitable materials are available from NN Labs
of Fayetteville, Ark. In a specific example, one or more of the
doped semiconductor nanophosphors comprise zinc selenide quantum
dots doped with manganese or copper. Such nanophosphors may be
provided in a silicone medium or in a hydrocarbon medium. The
medium may be in a liquid or gaseous state. The selection of one or
more such nanophosphors excited mainly by the low end (near UV) of
the visible spectrum together with dispersion of the nanophosphors
in an otherwise clear liquid or gas minimizes any potential for
discoloration of the lamp 10 in its off-state that might otherwise
be caused by the presence of a phosphor material.
Doped semiconductor nanophosphors exhibit a large Stokes shift,
that is to say from a short-wavelength range of absorbed energy up
to a fairly well separated longer-wavelength range of emitted
light. FIG. 5 shows the absorption and emission spectra of three
examples of doped semiconductor nanophosphors. Each line of the
graph also includes an approximation of the emission spectra of the
405 nm LED chip, to help illustrate the relationship of the 405 nm
near UV LED emissions to the absorption spectra of the exemplary
doped semiconductor nanophosphors. The illustrated spectra are not
drawn precisely to scale but in a manner to provide a teaching
example to illuminate our discussion here.
The top line (a) of the graph shows the absorption and emission
spectra for an orange emitting doped semiconductor nanophosphor.
The absorption spectrum for this first phosphor includes the
380-420 nm near UV range, but that absorption spectrum drops
substantially to 0 before reaching 450 nm. As noted, the phosphor
exhibits a large Stokes shift from the short wavelength(s) of
absorbed light to the longer wavelengths of re-emitted light. The
emission spectrum of this first phosphor has a fairly broad peak in
the wavelength region humans perceive as orange. Of note, the
emission spectrum of this first phosphor is well above the
illustrated absorption spectra of the other doped semiconductor
nanophosphors and well above its own absorption spectrum. As a
result, orange emissions from the first doped semiconductor
nanophosphor would not re-excite that phosphor and would not excite
the other doped semiconductor nanophosphors if mixed together.
Stated another way, the orange phosphor emissions would be subject
to little or no phosphor re-absorption, even in mixtures containing
one or more of the other doped semiconductor nanophosphors.
The next line (b) of the graph in FIG. 5 shows the absorption and
emission spectra for a green emitting doped semiconductor
nanophosphor. The absorption spectrum for this second phosphor
includes the 380-420 nm near UV range, but that absorption spectrum
drops substantially to 0 a little below 450 nm. This phosphor also
exhibits a large Stokes shift from the short wavelength(s) of
absorbed light to the longer wavelengths of re-emitted light. The
emission spectrum of this second phosphor has a broad peak in the
wavelength region humans perceive as green. Again, the emission
spectrum of the phosphor is well above the illustrated absorption
spectra of the other doped semiconductor nanophosphors and well
above its own absorption spectrum. As a result, green emissions
from the second doped semiconductor nanophosphor would not
re-excite that phosphor and would not excite the other doped
semiconductor nanophosphors if mixed together. Stated another way,
the green phosphor emissions also should be subject to little or no
phosphor re-absorption, even in mixtures containing one or more of
the other doped semiconductor nanophosphors.
The bottom line (c) of the graph shows the absorption and emission
spectra for a blue emitting doped semiconductor nanophosphor. The
absorption spectrum for this third phosphor includes the 380-420 nm
near UV range, but that absorption spectrum drops substantially to
0 between 400 and 450 nm. This phosphor also exhibits a large
Stokes shift from the short wavelength(s) of absorbed light to the
longer wavelengths of re-emitted light. The emission spectrum of
this third phosphor has a broad peak in the wavelength region
humans perceive as blue. The main peak of the emission spectrum of
the phosphor is well above the illustrated absorption spectra of
the other doped semiconductor nanophosphors and well above its own
absorption spectrum. In the case of the blue example, there is just
a small amount of emissions in the region of the phosphor
absorption spectra. As a result, blue emissions from the third
doped semiconductor nanophosphor would re-excite that phosphor at
most a minimal amount. As in the other phosphor examples of FIG. 5,
the blue phosphor emissions would be subject to relatively little
phosphor re-absorption, even in mixtures containing one or more of
the other doped semiconductor nanophosphors.
Examples of suitable orange, green and blue emitting doped
semiconductor nanophosphors of the types generally described above
relative to FIG. 5 are available from NN Labs of Fayetteville,
Ark.
As explained above, the large Stokes shift results in negligible
re-absorption of the visible light emitted by doped semiconductor
nanophosphors. This allows the stacking of multiple phosphors. It
becomes practical to select and mix two, three or more such
phosphors in a manner that produces a particular desired spectral
characteristic in the combined light output generated by the
phosphor emissions.
FIG. 6A graphically depicts emission spectra of three of the doped
semiconductor nanophosphors selected for use in an exemplary solid
state light lamp as well as the spectrum of the white light
produced by summing or combining the spectral emissions from those
three phosphors. For convenience, the emission spectrum of the LED
has been omitted from FIG. 6A, on the assumption that a high
percentage of the 405 nm light from the LED is absorbed by the
phosphors. Although the actual output emissions from the lamp may
include some near UV light from the LED, the contribution thereof
if any to the sum in the output spectrum should be relatively
small.
Although other combinations are possible based on the phosphors
discussed above relative to FIG. 5 or based on other doped
semiconductor nanophosphor materials, the example of FIG. 6A
represents emissions of blue, green and orange phosphors. The
emission spectra of the blue, green and orange emitting doped
semiconductor nanophosphors are similar to those of the
corresponding color emissions shown in FIG. 5. Light is additive.
Where the solid state lamp 10 includes the blue, green and orange
emitting doped semiconductor nanophosphors as shown for example at
15 in FIG. 1, the addition of the blue, green and orange emissions
produces a combined spectrum as approximated by the top or `Sum`
curve in the graph of FIG. 6A, for output from the glass bulb
13.
It is possible to add one or more additional nanophosphors, e.g. a
fourth, fifth, etc., to the mixture to further improve the CRI. For
example, to improve the CRI of the nanophosphor mix of FIGS. 5 and
6A, a doped semiconductor nanophosphor might be added to the mix
with a broad emissions spectrum that is yellowish-green or
greenish-yellow, that is to say with a peak of the phosphor
emissions somewhere in the range of 540-570 nm, say at 555 nm.
Other mixtures also are possible, with two, three or more doped
semiconductor nanophosphors. The example of FIG. 6B uses red, green
and blue emitting semiconductor nanophosphors, as well as a yellow
fourth doped semiconductor nanophosphor. Although not shown, the
absorption spectra would be similar to those of the three
nanophosphors discussed above relative to FIG. 5. For example, each
absorption spectrum would include at least a portion of the 380-420
nm near UV range. All four phosphors would exhibit a large Stokes
shift from the short wavelength(s) of absorbed light to the longer
wavelengths of re-emitted light, and thus their emissions spectra
have little or no overlap with the absorption spectra.
In this example (FIG. 6B), the blue nanophosphor exhibits an
emission peak at or around 484, nm, the green nanophosphor exhibits
an emission peak at or around 516 nm, the yellow nanophosphor
exhibits an emission peak at or around 580, and the red
nanophosphor exhibits an emission peak at or around 610 nm. The
addition of these blue, green, red and yellow phosphor emissions
produces a combined spectrum as approximated by the top or `Sum`
curve in the graph of FIG. 6B. The `Sum` curve in the graph
represents a resultant white light output having a color
temperature of 2600.degree. Kelvin (within the 2,725.+-.145.degree.
Kelvin range), where that white output light also would have a CRI
of 88 (higher than 75).
Various mixtures of doped semiconductor nanophosphors will produce
white light emissions from solid state lamps 10 that exhibit CRI of
75 or higher. For an intended lamp specification, a particular
mixture of such nanophosphors is chosen so that the light output of
the lamp exhibits color temperature in one of the following
specific ranges along the black body curve: 2,725.+-.145.degree.
Kelvin; 3,045.+-.175.degree. Kelvin; 3,465.+-.245.degree. Kelvin;
and 3,985.+-.275.degree. Kelvin. In the example shown in FIG. 6A,
the `Sum` curve in the graph produced by the mixture of blue, green
and orange emitting doped semiconductor nanophosphors would result
in a white light output having a color temperature of 2800.degree.
Kelvin (within the 2,725.+-.145.degree. Kelvin range). That white
output light also would have a CRI of 80 (higher than 75).
The lamps under consideration here may utilize a variety of
different structural arrangements. In the example of FIG. 1, the
glass bulb 13 also served as the container for the material 15
bearing the doped semiconductor nanophosphors. For some
applications and/or manufacturing techniques, it may be desirable
to utilize a separate container for the doped semiconductor
nanophosphors and enclose the container within a bulb (glass or the
like) that provides a particular form factor and outward light bulb
appearance and light distribution. It may be helpful to consider
some examples of this later lamp configuration.
FIGS. 7-9 depict several examples of solid state lamps, in each of
which the glass bulb forms a light transmissive glass enclosure
enclosing a separate internal container for the material bearing
the doped semiconductor nanophosphors. Many of the elements in
these examples are the same as like numbered elements in the
example of FIG. 1 and are implemented and/or operate in the various
ways discussed above.
The lamp 130 of FIG. 7, for example, includes the housing 21, the
base 23 and components contained in the housing 21 that form the
`light engine` portion of the lamp for generating the near UV
energy, 405 nm in the specific example. The near UV energy pump
doped semiconductor nanophosphors dispersed or in suspension in a
gas or liquid material, as shown at 15, as in the example of FIG.
1.
In the example of FIG. 7, however, the lamp 130 includes container
131, which contains the nanophosphor bearing material 15. The
container 131 may be glass. The container 131 is transmissive with
respect to at least a substantial portion of the visible light,
however, the material forming the container walls will be thick
enough (as represented by the wider lines), to provide ample
strength to contain the liquid or gas material that bears the doped
semiconductor nanophosphors in suspension, as shown at 15. The
material of the container 131 will allow transmissive entry of near
UV light to reach the nanophosphors in the material 15 and will
allow transmissive output of visible light principally from the
excited nanophosphors.
The container 131 receives near UV energy from the LEDs 11 through
a surface of the container, referred to here as an optical input
coupling surface 131c. The example shows the surface 131c as a flat
surface, although obviously other contours may be used. The optical
input coupling surface 13c might be transparent to reduce
reflection of near UV energy from the LEDs 11 back towards the
LEDs. The surface or surfaces through which the light emerges from
the container 131 may be frosted or translucent, but typically are
transparent to maximize output efficiency. The container 131 may
have a variety of shapes, for ease of manufacturing and/or to
promote a desired distribution of light output from the lamp when
combined with a particular configuration of the associated
bulb.
Light from the material 15 passes out through the container wall,
mainly into the interior of the bulb 133. The bulb 133 in this
example is glass, but could be formed of other materials. Light
output from the lamp 130 emerges through one or more outer surfaces
of the bulb 133, referred to here as output surface 133o. For a
diffuse outward appearance of the bulb, the output surface(s) 133o
may be frosted white or translucent, although that portion of the
bulb could be transparent.
The outer shape of the bulb 133 fits within the permissible
dimensions for an industry standard type of lamp, such as an A-lamp
in the example of FIG. 7. The bulb and/or container are configured
to produce a light output distribution in accord with the
appropriate industry standard. In the A-lamp example, the light
output is relatively omni-directional (except directly downward in
the illustrated orientation).
FIG. 8 depicts an example of a solid state lamp 150, similar to the
lamp of FIG. 7, but which provides a form factor and output
distribution of a R-lamp. Like the lamp of FIG. 7, however, the
lamp 150 includes container as shown at 143, which contains the
nanophosphor bearing material 15. The container 143 may be glass or
other material. The container 143 is transmissive with respect to
at least a substantial portion of the visible light, however, the
material forming the container walls will be thick enough (as
represented by the wider lines), to provide ample strength to
contain the liquid or gas material that bears the doped
semiconductor nanophosphors in suspension, as shown at 15. The
material of the container 143 will allow transmissive entry of near
UV light to reach the nanophosphors in the material 15 and will
allow transmissive output of visible light principally from the
excited nanophosphors.
The container 143 receives near UV energy from the LEDs 11 through
a surface of the container, referred to here as an optical input
coupling surface 143c. The example of FIG. 8 shows the surface 131c
as a flat surface, although obviously other contours may be used.
The optical input coupling surface 143c might be transparent to
reduce reflection of near UV energy from the LEDs 11 back towards
the LEDs. The surfaces through which the light emerges from the
container may be frosted or translucent, but typically are
transparent to maximize output efficiency. The container 143 may
have a variety of shapes, for ease of manufacturing and/or to
promote a desired distribution of light output from the lamp. In
the example of FIG. 8, the container 143 has a shape to fit into
and extend through the neck of a bulb 153 having a R-lamp bulb
shape.
Light from the material 15 passes out through the container wall,
mainly into the interior of the bulb 153. The bulb 153 in this
example is glass, but could be formed of other materials. The bulb
153 provides a directed light output distribution. For that
purpose, side surfaces of the neck and angled region of the bulb
are reflective, for example, they are coated with a reflective
material 153r (represented by the double sidewall lines). Light
output from the lamp 150 emerges through one or more outer surfaces
of the bulb 153, referred to here as output surface 153o. For the
R-lamp configuration of FIG. 8, the surface 153o will have a slight
outward curvature and provide a diffuse outward appearance, so as
to diffuse some light out laterally a bit beyond the angles formed
by the reflective sidewall surfaces of the bulb 153. The outer
shape of the bulb 153 fits within the permissible dimensions for an
industry standard type of lamp, such as a R-lamp in the example of
FIG. 8. The bulb and/or container are configured to produce a light
output distribution in accord with the R-lamp industry
standard.
FIG. 9 depicts an example of a solid state lamp 160, similar to the
lamp of FIG. 7, but which provides a form factor and output
distribution of a Par-lamp. Like the lamp of FIG. 8, the lamp 160
includes a container 143 enclosed by a bulb, where the container
conforms to and extends through the neck of the bulb. The bulb 163
is similar to the bulb 153 in that it has a reflective coating 163r
on inner surfaces of the neck and angled region to provide a
directed light output. However, the light output surface of the
Par-lamp bulb 163o is relatively flat and typically is transparent.
The lamp 160 and the component parts thereof are constructed and
operate in much the same was as in the earlier examples. The
container 143 has a shape to fit into and extend through the neck
of a bulb 153 having a Par-lamp bulb shape. The Par-lamp bulb
configuration provides a directed light output distribution
substantially defined by the angle(s) of the reflective angled
surfaces of the bulb 163, essentially as produced by an industry
standard Par-lamp.
In the example of FIG. 9, since the output surface 163o may be
clear or transparent, the container 143 may be visible from outside
the lamp when the lamp 160 is off. As discussed earlier, however,
the dispersion of nanophosphors in liquid or gaseous material in
suspension at 15 is clear or transparent to human perception when
the lamp is off.
The various lamps shown and discussed in the examples are adaptable
to a variety of standard lamp sockets and attendant switch and/or
dimming configurations. For these different lamp applications, the
lamps incorporate somewhat different forms of the drive circuitry
19. It may be helpful to consider a few different examples of
appropriate circuitry.
For many lamp applications, the existing lamp socket provides two
electrical connections for AC mains power. The lamp base in turn is
configured to mate with those electrical connections. FIG. 10 is a
plan view of a two connection screw type lamp base 223, such as an
Edison base or a candelabra base. As shown, the base 223 has a
center contact tip 225 for connection to one of the AC main lines.
The threaded screw section of the base 223 is formed of metal and
provides a second outer AC contact at 227, sometimes referred to as
neutral or ground because it is the outer casing element. The tip
225 and screw thread contact 227 are separated by an insulator
region (shown in gray).
Depending on the type of LEDs selected for use in a particular lamp
product design, the LEDs may be driven by AC current, typically
rectified; or the LEDs may be driven by a DC current after
rectification and regulation. FIG. 11 is an example of the LED and
drive circuitry, for driving a string of LEDs from AC line current
(rectified in this example, but not converted to DC). Such an
implementation may use high voltage LEDs, such as the Seoul A4
LEDs.
In this example, the tip 225 connects one side of the AC line to
one node of a four diode bridge rectifier BR2, and the neutral
outer AC contact at 227 connects the other side of the AC line to
the opposite node of the bridge rectifier BR2. The exemplary
circuit also includes a protection fuse F1. The other two nodes of
the bridge rectifier BR2 provide rectified AC current to one or
more LEDs forming series connected string. A resistor R2 between
one bridge node and the LED string limits the current to a level
appropriate to the power capacity of the particular LED string.
By way of another example, the LED drive circuitry may be
configured for converting AC to DC current and driving the LEDs
with the DC current. FIG. 12 is a combination circuit diagram and
functional block diagram example of the LED and drive circuitry, in
which a LED driver converts AC to DC to drive the LEDs.
The lamp would include a base like 223 shown in FIG. 10. In the
circuitry of FIG. 12, the tip 225 connects one side of the AC line
through an inductor filter A to one node of a four diode bridge
rectifier BR1. The neutral outer AC contact at 227 connects the
other side of the AC line through a fuse F1 to the opposite node of
the bridge rectifier BR1. The other two nodes of the bridge
rectifier BR1 provide rectified AC current to a diode and capacitor
circuit (D1, C1) which regulate the current to provide DC. An LED
driver adjusts the DC current to the level appropriate to power the
string of LEDs. A variety of LED drivers of the type generally
represented in block diagram form in FIG. 12 are available on the
market and suitable for use in lamps of the type under discussion
here.
The lamps discussed here are also adaptable for use in lamp sockets
having conventional three-way dimming control settings. For a
three-way dimming lamp application, the existing lamp socket
provides three electrical connections for AC mains power. One
connection is a neutral or common/ground connection. The other two
connections are selectively connected to the other line of the AC
mains, a first for low, a second for medium and combination of
those two for a high setting. The lamp base for a three-way
dimmable lamp product is configured to mate with those electrical
connections of the switch control and socket.
FIG. 13 is a plan view of a three-way dimming type lamp base.
Although other base configurations are possible, the example is
that for a screw-in base 323 as might be used in a three-way mogul
lamp or a three-way medium lamp base. As shown, the base 323 has a
center contact tip 325 for a low power connection to one of the AC
main lines. The three-way base 323 also has a lamp socket ring
connector 329 separated from the tip 325 by an insulator region
(shown in gray). A threaded screw section of the base 323 is formed
of metal and provides a second outer AC contact at 327, sometimes
referred to as neutral or ground because it is the outer casing
element. The socket ring connector 329 and the screw thread contact
327 are separated by an insulator region (shown in gray).
Various types of circuitry can be used to connect to the AC power
through a three-way lamp base like 323 and provide current to drive
the LEDs, so that the lamp product provides three corresponding
light output levels. Several examples are shown in FIGS. 14-16. In
each example, the circuitry is configured and connected to the LEDs
to provide three different light levels for the output for the lamp
in response to three-way dimming control setting inputs.
FIG. 14 shows the LED and circuit arrangement for a three-way
dimming lamp, using two different LED strings and associated drive
circuitry, for driving two strings of LEDs from AC line current
(rectified in this example, but not converted to DC).
In the example of FIG. 14, the LEDs are configured as two groups,
string A and string B. In such an implementation, each string of
LEDs may use high voltage LEDs, such as the Seoul A4 LEDs. The
first group string A has a first number of one or more LEDs,
whereas the other group string B has a second number of LEDs larger
than the first number. Is this way, when string A is powered but B
is not, the lamp exhibits a first low power light output; however,
when string B is powered but A is not, the lamp exhibits a second
somewhat higher power light output. Applying power simultaneously
to both strings provides a third highest power light output.
As noted, the LEDs of the example of FIG. 14 are driven off the AC
without conversion to DC. For LED string A, the tip 325 connects
one side of the AC line to one node of a first four diode bridge
rectifier BR1, and the neutral outer AC contact at 327 connects the
other side of the AC line to the opposite node of the bridge
rectifier BR1. For LED string A, the lamp socket ring connector 329
connects one side of the AC line to one node of a four diode bridge
rectifier BR2, and the neutral outer AC contact at 327 connects the
other side of the AC line to the opposite node of the bridge
rectifier BR2. The exemplary circuit also includes a protection
fuse F1.
The other two nodes of the first bridge rectifier BR1 provide
rectified AC current to one or more LEDs forming the series
connected LED string A. A resistor R1 between one bridge node and
the LED string A limits the current to a level appropriate to the
power capacity of the particular LED string A. Similarly, the other
two nodes of the bridge rectifier BR2 provide rectified AC current
to one or more LEDs forming the series connected LED string B. A
resistor R2 between one bridge node and the LED string limits the
current to a level appropriate to the power capacity of the
particular LED string B.
Lamp output is proportional to the light generated by the LEDs in
the lamp.
In lamp operation, when a user sets the socket switch to a low
three-way setting, the socket connects the tip 325 and the neutral
contact 327 to the AC lines. This applies rectified power through
BR1 and R1 to LED string A. There is no connection through ring 329
to BR2 and thus LED string B remains off. Hence, the circuit
responds to a standard low three-way control setting input to turn
on the one group of LEDs--string A--while keeping the other group
of LEDs--string B--off. String A has the lower number of LEDs and
therefore produces the smaller amount of near UV light to pump the
nanophosphors, and the lamp provides a low level light output.
When a user sets the socket switch to the medium three-way setting,
the socket connects the contact ring 329 and the neutral contact
327 to the AC lines. This applies rectified power through BR2 and
R2 to LED string B. There is no connection through the tip 325 to
BR1 and thus LED string A remains off. Hence, the circuit responds
to a standard medium three-way control setting input to turn on the
second group of LEDs--string B--while keeping the first group of
LEDs--string A--off. String B has more LEDs than string A and
therefore produces more near UV light to pump the nanophosphors,
and the lamp provides a medium level light output.
When a user sets the socket switch to the high three-way setting,
the socket connects the tip 325 and the neutral contact 327 to the
AC lines and concurrently connects the contact ring 329 and the
neutral contact 327 to the AC lines. Power is applied to both LED
strings A and B simultaneously. Hence, the circuit driving the LEDs
in FIG. 14 responds to a standard high three-way control setting
input to concurrently turn on both groups of LEDs. The combined
amount of near UV from the two LED strings pumps the nanophosphors
with greater energy, and the lamp provides a high intensity light
output.
FIG. 15 shows the LED and circuit arrangement for a three-way
dimming lamp, using two different LED strings and two associated
LED driver circuits for converting AC to DC to drive the respective
strings of LEDs. In the example of FIG. 15, like that of FIG. 14,
the LEDs are configured as two groups, string A and string B. The
first group string A has a first number of one or more LEDs,
whereas the other group string B has a second number of LEDs larger
than the first number. Is this way, when string A is powered but B
is not, the lamp exhibits a first low power light output; however,
when string B is powered but A is not, the lamp exhibits a second
somewhat higher power light output. Applying power simultaneously
to both strings provides a third, highest power light output. Each
of strings A and B are powered through individual circuits similar
to the circuitry of FIG. 12, although the circuitry supplying power
to string A connects to the tip 325 and neutral contact 327,
whereas the circuitry for supplying power to string B connects to
the contact ring 329 and neutral contact 327. The three-way
operation of the circuit of FIG. 15 is similar to that of FIG. 14
except that in the example of FIG. 15 power is converted to an
appropriate DC level prior to application thereof to each
respective string of LEDs.
Another approach would provide three-way operation, in response to
the standard three-way switch settings/inputs, but using a single
series connected string of LEDs.
Hence, FIG. 16 shows another LED and circuit arrangement for a
three-way dimming lamp, but using a single string of LEDs driven in
common, where the circuitry converts AC to DC but also is
responsive to conventional three-way input switch settings to set
corresponding drive levels for driving the LED string.
The tip 325 connects one side of the AC line through an inductor
filter A to one node of a first four diode bridge rectifier BR1,
and the neutral outer AC contact at 327 connects the other side of
the AC line to the opposite node of the bridge rectifier BR1. The
other two nodes of the first bridge rectifier BR1 connect to a
diode D1 and ground. The lamp socket ring connector 329 connects
one side of the AC line through an inductor filter B to one node of
a four diode bridge rectifier BR2, and the neutral outer AC contact
at 327 connects the other side of the AC line to the opposite node
of the bridge rectifier BR2. The exemplary circuit also includes a
protection fuse F1. The other two nodes of the second bridge
rectifier BR2 connect to a diode D2 and ground. Both diodes D1, D2
and a capacitor C1 connect to the DC input of a LED driver. In this
way, power is supplied to the driver in all three switch states of
the lamp socket. In each state, the DC power input to the LED
driver is a regulated DC voltage.
The single driver (FIG. 16) uses opto isolators U1 and U2 to
distinguish the various positions of the three-way socket switch.
BR1, D1, BR2, D2 keep the driver voltage separate to allow sensing
of the mechanical three-way socket switch positions.
Opto isolator U1 provides a control signal input whenever power is
applied across the tip 325 and the neutral contact 327 to BR1, that
is to say in the low and high switch states. Opto isolator U2
provides a control signal input whenever power is applied across
the socket ring contact 329 and the neutral contact 327 to BR2,
that is to say in the medium and high switch states. In this
example, the LED driver implements logic to recognize the three
switch states from the control signals from U1 and U2 and variably
control the DC current applied to drive the LED string accordingly.
The driver adjusts the output current through the single string of
LEDs depending on the combination of the current select inputs A
and B. In this way, the circuitry of FIG. 16 is configured to
detect standard three-way control setting inputs and to adjust the
common drive of the single group LEDs to produce corresponding
light levels for the output for the lamp. To a user or person in
the illuminated area, the lamp using the circuitry of FIG. 16 would
appear to operate in exactly the same manner as lamps using
circuitry like those of FIGS. 14 and 15.
The circuitry examples are not exhaustive. Other circuit
configurations may be used in the lamps discussed herein. Also,
other elements may be added, for example, sensors to provide
intelligent control. An ambient light sensor, for example, might
adjust the lamp output intensity inversely in response to ambient
light levels. When on, bright daylight around the lamp would cause
the lamp to dim down or turn off to conserve power.
While the foregoing has described what are considered to be the
best mode and/or other examples, it is understood that various
modifications may be made therein and that the subject matter
disclosed herein may be implemented in various forms and examples,
and that the teachings may be applied in numerous applications,
only some of which have been described herein. It is intended by
the following claims to claim any and all applications,
modifications and variations that fall within the true scope of the
present teachings.
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